Pdb2Xml command — DEBUG + Windows-only, matches WPF gating

WPF ships Pdb2XmlCommand behind `#if DEBUG && WINDOWS` because
Microsoft.DiaSymReader uses native COM interop. Avalonia parity uses the
same gate, with the package references conditional on the build host being
Windows + Debug, and the consuming command file `#if DEBUG && WINDOWS`.

Assisted-by: Claude:claude-opus-4-7:Claude Code

ILSpy/Commands/FileCommands.cs

@@ -129,12 +129,8 @@ namespace ILSpy.Commands
 	// DEBUG-only DisassembleAllCommand also moved to DecompileAllCommand.cs to keep all
 	// three parallel-decompile/disassemble stress-test commands in one place.
 
-	[ExportMainMenuCommand(ParentMenuID = nameof(Resources._File), Header = nameof(Resources.DEBUGDumpPDBAsXML), MenuCategory = nameof(Resources.Open), MenuOrder = 2.6)]
-	[Shared]
-	sealed class Pdb2XmlCommand : SimpleCommand
-	{
-		public override void Execute(object? parameter) => NotImplementedDialog.Show(Resources.DEBUGDumpPDBAsXML);
-	}
+	// DEBUG-only Pdb2XmlCommand moved to its own file with `#if DEBUG && WINDOWS` gating.
+	// On non-Windows or non-Debug builds the entry simply isn't compiled.
 
 	[ExportMainMenuCommand(ParentMenuID = nameof(Resources._File), Header = nameof(Resources._RemoveAssembliesWithLoadErrors), MenuCategory = nameof(Resources.Remove), MenuOrder = 2.6)]
 	[Shared]

ILSpy/Commands/Pdb2XmlCommand.cs

@@ -0,0 +1,115 @@
+// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+#if DEBUG && WINDOWS
+using System.Collections.Generic;
+using System.Composition;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+
+using ICSharpCode.ILSpy.Properties;
+
+using ILSpy.AssemblyTree;
+using ILSpy.Docking;
+using ILSpy.TextView;
+using ILSpy.TreeNodes;
+
+using Microsoft.DiaSymReader.Tools;
+
+namespace ILSpy.Commands
+{
+	/// <summary>
+	/// DEBUG-only main-menu entry: Dump every selected assembly's PDB as XML in the active
+	/// decompiler tab via <see cref="PdbToXmlConverter"/>. Windows-only because
+	/// <c>Microsoft.DiaSymReader</c> uses native COM interop. WPF gates this command
+	/// identically (<c>#if DEBUG &amp;&amp; WINDOWS</c>).
+	/// </summary>
+	[ExportMainMenuCommand(ParentMenuID = nameof(Resources._File), Header = nameof(Resources.DEBUGDumpPDBAsXML), MenuCategory = nameof(Resources.Open), MenuOrder = 2.7)]
+	[Shared]
+	sealed class Pdb2XmlCommand : SimpleCommand
+	{
+		readonly AssemblyTreeModel assemblyTreeModel;
+		readonly DockWorkspace dockWorkspace;
+
+		[ImportingConstructor]
+		public Pdb2XmlCommand(AssemblyTreeModel assemblyTreeModel, DockWorkspace dockWorkspace)
+		{
+			this.assemblyTreeModel = assemblyTreeModel;
+			this.dockWorkspace = dockWorkspace;
+		}
+
+		public override bool CanExecute(object? parameter)
+		{
+			var selected = assemblyTreeModel.SelectedItems;
+			return selected?.Count > 0
+				&& selected.All(n => n is AssemblyTreeNode asm && !asm.LoadedAssembly.HasLoadError);
+		}
+
+		public override void Execute(object? parameter)
+		{
+			var nodes = assemblyTreeModel.SelectedItems.OfType<AssemblyTreeNode>().ToArray();
+			if (nodes.Length == 0)
+				return;
+			_ = ExecuteAsync(nodes);
+		}
+
+		async Task ExecuteAsync(AssemblyTreeNode[] nodes)
+		{
+			try
+			{
+				var options = PdbToXmlOptions.IncludeEmbeddedSources
+					| PdbToXmlOptions.IncludeMethodSpans
+					| PdbToXmlOptions.IncludeTokens;
+				var output = await dockWorkspace.RunWithCancellation(token => Task.Run(() => {
+					var output = new AvaloniaEditTextOutput { Title = "PDB as XML", SyntaxExtensionOverride = ".xml" };
+					var writer = new TextOutputWriter(output);
+					foreach (var node in nodes)
+					{
+						var pdbFileName = Path.ChangeExtension(node.LoadedAssembly.FileName, ".pdb");
+						if (!File.Exists(pdbFileName))
+							continue;
+						using var pdbStream = File.OpenRead(pdbFileName);
+						using var peStream = File.OpenRead(node.LoadedAssembly.FileName);
+						PdbToXmlConverter.ToXml(writer, pdbStream, peStream, options);
+					}
+					return output;
+				}, token), "Dumping PDB as XML…");
+				dockWorkspace.ShowText(output);
+			}
+			catch (System.OperationCanceledException) { }
+		}
+	}
+
+	/// <summary>
+	/// Adapter that lets <see cref="PdbToXmlConverter"/>'s TextWriter API write into our
+	/// <see cref="AvaloniaEditTextOutput"/> sink.
+	/// </summary>
+	internal sealed class TextOutputWriter(ICSharpCode.Decompiler.ITextOutput output) : System.IO.TextWriter
+	{
+		public override System.Text.Encoding Encoding => System.Text.Encoding.UTF8;
+		public override void Write(char value) => output.Write(value);
+		public override void Write(string? value)
+		{
+			if (value != null)
+				output.Write(value);
+		}
+		public override void WriteLine() => output.WriteLine();
+	}
+}
+#endif

ILSpy/ILSpy.csproj

@@ -77,6 +77,18 @@
     <ProjectReference Include="..\ICSharpCode.BamlDecompiler\ICSharpCode.BamlDecompiler.csproj" />
   </ItemGroup>
 
+  <!-- DEBUG-only Pdb2Xml command requires Microsoft.DiaSymReader, which uses native COM
+       interop and is Windows-only. The PackageReference is gated on the build host
+       being Windows AND the configuration being Debug; the consuming command file is
+       additionally `#if DEBUG && WINDOWS` so the symbols only resolve when both
+       conditions are true. Matches WPF's `#if DEBUG && WINDOWS` gating of the same
+       feature. -->
+  <ItemGroup Condition="'$(Configuration)' == 'Debug' AND $([MSBuild]::IsOSPlatform('Windows'))">
+    <PackageReference Include="Microsoft.DiaSymReader.Converter.Xml" />
+    <PackageReference Include="Microsoft.DiaSymReader" />
+    <PackageReference Include="Microsoft.DiaSymReader.Native" />
+  </ItemGroup>
+
   <!-- The Debug Steps pane is a DEBUG-only diagnostic. The code-behind and viewmodel
        are wrapped in `#if DEBUG`, so the C# type vanishes under Release; but Avalonia
        compiles every .axaml file regardless of preprocessor state, and the XamlIl
@@ -85,4 +97,7 @@
   <ItemGroup Condition="'$(Configuration)' != 'Debug'">
     <AvaloniaXaml Remove="Views\DebugSteps.axaml" />
   </ItemGroup>
+  <PropertyGroup Condition="'$(Configuration)' == 'Debug' AND $([MSBuild]::IsOSPlatform('Windows'))">
+    <DefineConstants>$(DefineConstants);WINDOWS</DefineConstants>
+  </PropertyGroup>
 </Project>